Method of waterproofing mineral wool



Patented Jan. 10, 1950 2,493,845 I C E METHOD OF WATERPROOFING MINERAL WOOL Joseph H. Zettel, Martinsville, N. L, assignor to- J ohns-Manville Corporation, New York, N.' 'Y., a corporation of New York No Drawing. Application July 2, 1945, Serial No. 602,929

2 Claims. (01.117-126) The instant invention relates to improvements in the production of mineral wool, particularly that to be employed in the form of nodules or other fibrous aggregates, or as loose wool and the like for thermal insulation and other purposes and, more particularly, to methods of treating the mineral wool to increase its resistance to moisture penetration. The term mineral wool is used herein in a generic sense to include wool or fibers formed from rock, slag, glass, mixtures thereof or other suitable raw materials.

As is well recognized in the art, where mineral wool is employed for its conventional purposes, for example, as a thermal insulating material, it is a matter of primary importance to protect the material against the entry of moisture, as moisture reduces its insulating efficiency, decreases its resistance to compaction and may have other deleterious effects. Heretofore, it has been proposed to overcome these obstacles by, for example, admixing with the wool a liquid waterproofing material such as a solution or suspension of a metallic stearate in oil, or the stearate in a molten state, preferably dissolved in a molten wax base. Such prior treatments, however, have themselves presented numerous disadvantages, particularly with respect to the difliculty of accurately controlling the amount of waterproofing material employed, the difficulty of handling and storing the hot solutions required, the adverse effects that they have had on the coverage properties of the mineral wool, and the like.

The principal object of the instant invention is the provision of an improved method of incorporating treating materials, such as waterrepellent materials with mineral wool fibers, the method substantially reducing, if not eliminating, the disadvantages of the prior methods.

Another object of the invention is the provision of such method in which the water-repellent or other treating material is handled and admixed with the wool in a dry state, whereby the making. and storing of hot solutions is not required. The method of the invention, furthermore, is one which imparts maximum moisture-resistance to the wool with minimum amounts of the treating material.

A further object of the invention is the pro vision of a method which gives mineral wood in creased coverage properties.

A further object of the invention is the provision of an improved nodulated mineral wool as formed by the method attaining the foregoing objects of the invention.

The method of the instant invention may be incorporated in known processes of manufacturing mineral wool such, for example, as the procedure involving the disintegrating of the molten stream of the selected raw material, such as,

rock, slag, glass or mixtures thereof, by subject, ing the molten stream to the action of a high pressure jet of steam or air. The invention is particularly. adapted, however, for usein conjunction with the more recently developed process involving the use of one or more spinners or rotors which are rotated at high speed and upon which the molten material impinges to be broken up into drops or masses which are thrown from the rotor by centrifugal force and thereby drawn out into filament or fiber form, as disclosed, for example, in the copending applications, 8. N. 466,067, filed November 18, 1942, now U. S. Patent No. 2,399,383, and S. N. 485,009, filed April 29, 1943, now U. S. Patent No. 2,428,810,. of Edward R. Powell. The .fibers produced by such opera tions are collected in suitable ways and, thereafter, utilized as loose mineral wool or converted into nodules, aggregates, mats, blankets or the like by. further operations.

A feature commonly used with the prior'con- I ventional methods, especially where the wool is to be employed in nodulated form for filling wall spaces in buildings and the like, consists in ad mixing a suitable, oleaginous material, such as;

petroleum oil, preferably fuel oil or paraflin oil in limited quantities with the fibers. The oil serves as a medium for preventing excessive dustiness, this feature being of particularv importance where the Wool in loose or nodulated form is to be pneumatically conveyed into wall spaces. The oil is added at a suitable point during the fiber forming operations to become broken up intofine particles and distributed among the newly formed fibers.

The instant invention includes a similar operation, the oleaginous liquid, preferably of the type of the oils previously employed having, however, important functions in addition to that of dust control. If the blowing system is employed for the production of .the mineral wool filaments the oil ispreferably added at the steam jet in In the spinning process of wool formation, the oil may be sprayed in finely divided or atomized form onto the fibers.

the conventional manner.

as they are formed or after their collection in the form of a relatively loose, fluffy layer. In both cases substantially uniform distribution of powdered form and the oil is employed in urficient amounts for this purpose.

A preferred water-repellent material is zinc:

stearate but other materials which impart water resistance to the wool, such as aluminum.

stearate,"'aluminum palmitate or other metallic soaps, waxes and other fatty acid compounds,

having water-repellent characteristics such as stearic acid or palmitic acid may be used. The

types and classes of materials-mentioned are particularly adapted to impart moisture resistance to the mineral wool as only a relatively small quantity of the materialis required to form a permanent and eifective water resistant coating on the fibers.

The water-repellent material in a dry,'finely powdered state may be admixed with the oiltreated fibers at a suitable stage in the operations, preferably after the collection of the fibers. Admixing is accomplished in an apparatus comp ising, for example, a rotating chamber into which the collected wooljis conveyedthe chamher having rotating paddles or the like whereby thepowdered material is distributed on the fibers Other mechanical or air suspension type mix'ers' other feeding means to the previously oil-treated,

wool and thoroughly intermixed therewith Due to' the presence of .the oil and its tendency to coat the individual fibers, the watererepellent material in its finely powderedstate is picked up by the oil andretained thereby on the fibers to exert its water-repellent action.

The water-repellent material ma be employed in relatively small amounts, say, in proportions of about 0.1% or less of the fibrous, admixture. It has been determined that this small proportion of a water-repellent material such as zinc stearate, admixed with the oil-treated fibers in the manner described, will impart a high degree of moisture resistance to the fibrous mass. Furthermore, the resultant mineral wool has higher coverage properties than mineral wool materials waterproofed byprior methods and doesnot exhibit the sogginess found where such prior methods are used. Also it has been found thatmineral wool treated by the, instantfmethod has a higher insulating efficiency "than wool waterproofed by other methods. For example, thermal conductivity tests were made on two samples of spun wool. Both samples were the same except that the first was treated with a wax so-. lution and the second Wastreated by thefinstant method. The first sample gave a 70' value of .385 at a density of 2.9 lbs. per cu; ft. The other sample had k values of .33 at a density of 3.2 lbs.

7 per cu. ft. and .341at a density of 2.6 lbs. percu.

ft.-, exhibiting about a 10% increase in insulat-. ingvalue. The method of the instant of'a molten wax to enable it to be applied to the fibers, no such large amount of'a carrier liquid is required. In addition, the method eliminates both the necessity of making solutions and of invention has the further advantage that the quantity of water proofing material maybe controlledas desired. Also, in contrast to the prior methods where the waterproofing agent, such as zinc stearate', was necessarily dissolved in relatively large quantities I melting and hot storing waxes, and'requires less manufacturing attention and maintenance.

As an example of the instant invention, in the production of waterproofed nodulated wool for use particularly in the insulating of wall spaces by pneumatic or blowing methods, a conventional oleaginous liquid such as fuel oil is applied to the fiber in amounts suflicient to provide about 0.10 to 0.80% of oil by weight of the admixture of oil and fiber. The oil serves its conventional function of controlling dustiness and, in addition, serves to collect and hold the waterproofing material on the fibers. The powdered water repellent, particularly zinc stearate, is employed. in .amounts suflicientto constitute about 0.05% to. 0.50%. by weight of; Application of the wa the admixture of fibers. terproofing material is preferably accomplished as previously stated, by suitable mechanical orair suspension mixers to which the wool is supplied in bulk form. The resulting treated wool then may be subjected to such further conven-.

tional steps necessary to produce nodulated or granulated mineral wool oi the desired type. The 1 of coverage after prolonged storage, unobtainable.

by prior known methods.

Having thus described my invention .in rather;

full detail it will be understbodfthat'these details need not be strictly adhered to but that various changes and modifications may suggest themselves to one. skilled in the art, allfalling; within the scope of. the invention as defined by the subjoined claims. What I claim is;

1. The method of treating newly formed min-,.

eral wool fibers comprising, admixing withthe fibers an oleaginous liquid coatingmaterial adjacent the point of formation of saidfibers to coat the fibers, and thereafter distributing onto said coated fibers a minor proportion of a powdered, water-repellent material selected from the group consistingv of waxes, [soap-forming fattyacids and metallic salts ofsoap-formingfatty. acids whereby said powdered, water-repellent. material is adhesively secured to the fibers by said oleaginous material. 1 2. The method of claim lin which the. oleaginous liquid is appliedinamounts of the order. of 0.10 to 0.80% by weight of the admixture,-and L the powdered, water-repellent material is applied in amounts of the order of 0.05 to 0.50% by weight of the admixture.

' JOSEPH I-I. ZETTEL.

REFERENCES CITED? The followingreferences are of record 4 file of this patent:

UNITED STATES PATENTS Great Britain Aug; 23,193 j 

1. THE METHOD OF TREATING NEWLY FORMED MINERAL WOOL FIBERS COMPRISING, ADMIXING WITH THE FIBERS AN OLEAGINOUS LIQUID COATING MATERIAL ADJACENT THE POINT OF FORMATION OF SAID FIBERS TO COAT THE FIBERS, AND THEREAFTER DISTRIBUTING ONTO SAID COATED FIBERS A MINOR PROPORTION OF A POWDERED, WATER-REPELLENT MATERIAL SELECTED FROM THE GROUP CONSISTING OF WAXES, SOAP-FORMING FATTY ACIDS AND METALLIC SALTS OF SOAP-FORMING FATTY ACIDS WHEREBY SAID POWDERED, WATER-REPELLENT MATERIAL IS ADHESIVELY SECURED TO THE FIBERS BY SAID OLEAGINOUS MATERIAL. 